This invention relates to ultrasonic data collection systems and is particularly concerned with problems arising when a number of ultrasonic transducers are sequentially and repetitively pulsed to give, from received echoes, a visual presentation of an object scanned by the transducers. One application of the invention arises with under-sodium viewing of components in a sodium-cooled fast reactor.
Ultrasonic imaging equipment customarily employs a computer-based echo recording device and means for controlling the repetition rate of pulses transmitted from the transducers of the equipment. Because of the finite time taken by the recording device to record echo data, the transmitted pulse repetition rate must be kept below a certain maximum. If this is not done, then the processing of data of one echo may prevent the recording of echoes sequentially received in the pulsing sequence. Further, if all the transducers are producing valid echoes, then alternate transducers will effectively be masked out. Systematically ignoring certain transducers can result in part of the target not being scanned and hence not imaged. One solution to this problem is to arrange for the repetition rate of pulses transmitted from the transducers to be reduced. This solution gives rise to loss of resolution in the imaging or increases the time to reach a given resolution.